TY - GEN A1 - Alhosseini Almodarresi Yasin, Seyed Ali A1 - Bin Tareaf, Raad A1 - Najafi, Pejman A1 - Meinel, Christoph T1 - Detect me if you can BT - Spam Bot Detection Using Inductive Representation Learning T2 - Companion Proceedings of The 2019 World Wide Web Conference N2 - Spam Bots have become a threat to online social networks with their malicious behavior, posting misinformation messages and influencing online platforms to fulfill their motives. As spam bots have become more advanced over time, creating algorithms to identify bots remains an open challenge. Learning low-dimensional embeddings for nodes in graph structured data has proven to be useful in various domains. In this paper, we propose a model based on graph convolutional neural networks (GCNN) for spam bot detection. Our hypothesis is that to better detect spam bots, in addition to defining a features set, the social graph must also be taken into consideration. GCNNs are able to leverage both the features of a node and aggregate the features of a node’s neighborhood. We compare our approach, with two methods that work solely on a features set and on the structure of the graph. To our knowledge, this work is the first attempt of using graph convolutional neural networks in spam bot detection. KW - Social Media Analysis KW - Bot Detection KW - Graph Embedding KW - Graph Convolutional Neural Networks Y1 - 2019 SN - 978-1-4503-6675-5 U6 - https://doi.org/10.1145/3308560.3316504 SP - 148 EP - 153 PB - Association for Computing Machinery CY - New York ER - TY - GEN ED - Plattner, Hasso ED - Meinel, Christoph ED - Leifer, Larry T1 - Design thinking : understand - improve - apply Y1 - 2011 SN - 978-3-642-13756-3 PB - Springer-Verlag Berlin Heidelberg CY - Berlin, Heidelberg ER - TY - GEN A1 - Fichte, Johannes Klaus A1 - Hecher, Markus A1 - Meier, Arne T1 - Counting Complexity for Reasoning in Abstract Argumentation T2 - The Thirty-Third AAAI Conference on Artificial Intelligence, the Thirty-First Innovative Applications of Artificial Intelligence Conference, the Ninth AAAI Symposium on Educational Advances in Artificial Intelligence N2 - In this paper, we consider counting and projected model counting of extensions in abstract argumentation for various semantics. When asking for projected counts we are interested in counting the number of extensions of a given argumentation framework while multiple extensions that are identical when restricted to the projected arguments count as only one projected extension. We establish classical complexity results and parameterized complexity results when the problems are parameterized by treewidth of the undirected argumentation graph. To obtain upper bounds for counting projected extensions, we introduce novel algorithms that exploit small treewidth of the undirected argumentation graph of the input instance by dynamic programming (DP). Our algorithms run in time double or triple exponential in the treewidth depending on the considered semantics. Finally, we take the exponential time hypothesis (ETH) into account and establish lower bounds of bounded treewidth algorithms for counting extensions and projected extension. Y1 - 2019 SN - 978-1-57735-809-1 SP - 2827 EP - 2834 PB - AAAI Press CY - Palo Alto ER - TY - GEN A1 - Fabian, Benjamin A1 - Baumann, Annika A1 - Ehlert, Mathias A1 - Ververis, Vasilis A1 - Ermakova, Tatiana T1 - CORIA - Analyzing internet connectivity risks using network graphs T2 - 2017 IEEE International Conference on Communications (ICC) N2 - The Internet can be considered as the most important infrastructure for modern society and businesses. A loss of Internet connectivity has strong negative financial impacts for businesses and economies. Therefore, assessing Internet connectivity, in particular beyond their own premises and area of direct control, is of growing importance in the face of potential failures, accidents, and malicious attacks. This paper presents CORIA, a software framework for an easy analysis of connectivity risks based on large network graphs. It provides researchers, risk analysts, network managers and security consultants with a tool to assess an organization's connectivity and paths options through the Internet backbone, including a user-friendly and insightful visual representation of results. CORIA is flexibly extensible in terms of novel data sets, graph metrics, and risk scores that enable further use cases. The performance of CORIA is evaluated by several experiments on the Internet graph and further randomly generated networks. KW - risk analysis KW - connectivity KW - graph analysis KW - complex networks KW - Internet Y1 - 2017 SN - 978-1-4673-8999-0 SN - 978-1-4673-9000-2 U6 - https://doi.org/10.1109/ICC.2017.7996828 SN - 1550-3607 PB - IEEE CY - Piscataway ER - TY - GEN A1 - Klieme, Eric A1 - Tietz, Christian A1 - Meinel, Christoph T1 - Beware of SMOMBIES BT - Verification of Users based on Activities while Walking T2 - The 17th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (IEEE TrustCom 2018)/the 12th IEEE International Conference on Big Data Science and Engineering (IEEE BigDataSE 2018) N2 - Several research evaluated the user's style of walking for the verification of a claimed identity and showed high authentication accuracies in many settings. In this paper we present a system that successfully verifies a user's identity based on many real world smartphone placements and yet not regarded interactions while walking. Our contribution is the distinction of all considered activities into three distinct subsets and a specific one-class Support Vector Machine per subset. Using sensor data of 30 participants collected in a semi-supervised study approach, we prove that unsupervised verification is possible with very low false-acceptance and false-rejection rates. We furthermore show that these subsets can be distinguished with a high accuracy and demonstrate that this system can be deployed on off-the-shelf smartphones. KW - gait KW - authentication KW - smartphone KW - activities KW - verification KW - behavioral KW - continuous Y1 - 2018 SN - 978-1-5386-4387-7 SN - 978-1-5386-4389-1 U6 - https://doi.org/10.1109/TrustCom/BigDataSE.2018.00096 SN - 2324-9013 SP - 651 EP - 660 PB - IEEE CY - New York ER - TY - GEN A1 - Schäpers, Björn A1 - Niemueller, Tim A1 - Lakemeyer, Gerhard A1 - Gebser, Martin A1 - Schaub, Torsten H. T1 - ASP-Based Time-Bounded Planning for Logistics Robots T2 - Twenty-Eighth International Conference on Automated Planning and Scheduling (ICAPS 2018) N2 - Manufacturing industries are undergoing a major paradigm shift towards more autonomy. Automated planning and scheduling then becomes a necessity. The Planning and Execution Competition for Logistics Robots in Simulation held at ICAPS is based on this scenario and provides an interesting testbed. However, the posed problem is challenging as also demonstrated by the somewhat weak results in 2017. The domain requires temporal reasoning and dealing with uncertainty. We propose a novel planning system based on Answer Set Programming and the Clingo solver to tackle these problems and incentivize robot cooperation. Our results show a significant performance improvement, both, in terms of lowering computational requirements and better game metrics. Y1 - 2018 SN - 2334-0835 SN - 2334-0843 SP - 509 EP - 517 PB - ASSOC Association for the Advancement of Artificial Intelligence CY - Palo Alto ER - TY - GEN A1 - Xenikoudakis, Georgios A1 - Ahmed, Mayeesha A1 - Harris, Jacob Colt A1 - Wadleigh, Rachel A1 - Paijmans, Johanna L. A. A1 - Hartmann, Stefanie A1 - Barlow, Axel A1 - Lerner, Heather A1 - Hofreiter, Michael T1 - Ancient DNA reveals twenty million years of aquatic life in beavers T2 - Current biology : CB N2 - Xenikoudakis et al. report a partial mitochondrial genome of the extinct giant beaver Castoroides and estimate the origin of aquatic behavior in beavers to approximately 20 million years. This time estimate coincides with the extinction of terrestrial beavers and raises the question whether the two events had a common cause. Y1 - 2020 U6 - https://doi.org/10.1016/j.cub.2019.12.041 SN - 0960-9822 SN - 1879-0445 VL - 30 IS - 3 SP - R110 EP - R111 PB - Current Biology Ltd. CY - London ER - TY - GEN A1 - Frank, Mario A1 - Kreitz, Christoph T1 - A theorem prover for scientific and educational purposes T2 - Electronic proceedings in theoretical computer science N2 - We present a prototype of an integrated reasoning environment for educational purposes. The presented tool is a fragment of a proof assistant and automated theorem prover. We describe the existing and planned functionality of the theorem prover and especially the functionality of the educational fragment. This currently supports working with terms of the untyped lambda calculus and addresses both undergraduate students and researchers. We show how the tool can be used to support the students' understanding of functional programming and discuss general problems related to the process of building theorem proving software that aims at supporting both research and education. Y1 - 2018 U6 - https://doi.org/10.4204/EPTCS.267.4 SN - 2075-2180 IS - 267 SP - 59 EP - 69 PB - Open Publishing Association CY - Sydney ER -